Micro-mechanical modulators have been known for some time. Generally, a micro-mechanical light modulator consists of a substrate, usually made of silicon and containing active driving circuitry, and an array of miniature cantilevered beams serving as deflecting mirrors.
The entire mirror array is usually illuminated simultaneously by a single light source. When a voltage is applied to a particular beam, it tips down toward the ground electrode located on the substrate, while deflecting the incident light in the process. By applying voltage to selected beams, and causing them to deflect, light modulation is accomplished.
To improve the density and decrease the cost of the modulator, the mirrors are often fabricated in two interdigitated rows. This arrangement generates corresponding staggered output light patterns which necessitate electronic pre-processing of the data prior to printing. Such pre-processing may involve electronic buffering and interlacing of the data which significantly complicates the operation of the overall printing system.
Furthermore, because every printed line consists of two half-lines which are printed at different times by the modulator mirror rows, the quality of printing depends to a large extent on the uniformity of the relative movement of the modulator and the medium being printed.